1. Field of the Invention
The invention relates to an X-ray examination apparatus of the type having a stand with a base, an arm arrangement with a first end mounted for rotation around a first vertical shaft that is attached to the base and with a second end that carries a support, which is mounted for rotation around a second vertical shaft, whereby the support is connected to a holding device, with a curved carrier displaceably arranged therein, with an X-ray tube and a radiation receiver mounted opposite each other at opposite ends of the carrier, and with an examination table.
2. Description of the Prior Art
In connection with X-ray examinations with an apparatus of the aforementioned known type, an examination table is utilized, which can be displaced at least along its longitudinal direction It is of great advantage with respect to a heart examination, for example, when the curved carrier of the stand can be moved from a head-adjusted position, in which the stand and the carrier are arranged behind the top end of the examination table and in which the top end is placed between the X-ray tube and the radiation detector, into a lateral position, in which the carrier, in a vertical position, is perpendicularly arranged relative to the fictive center axis of the examination table, while the isocenter stays in the same location in space. It is also of great advantage when the carrier can be rotated 180xc2x0 from the described lateral position into a mirror-inverted lateral position at the other side of the table, also while the isocenter stays fixed. Thus, the physician""s team has wide-ranging access to the patient.
U.S. Pat. No. 4,922,512 describes an X-ray examination stand of the aforementioned type. The base, around whose shaft the arm and the support are rotatably connected, is attached to the floor below the top end of the examination table. Due to the arm extending under the table and due to the vertical shaft of the base being in axial alignment with a center line between the X-ray tube and the receptor, the stand with the carrier for the X-ray tube and the detector can be rotated from a centrally head-adjusted position into a position, in which the carrier is arranged at an angle of 90xc2x0 in relationship to the longitudinal direction of the table without changing the position of the isocenter. Proceeding from this described position, the stand and the carrier always can be rotated by 180xc2x0 into a corresponding position at the other side of the examination table, again without changing the position of the isocenter. Since the arm at the floor is relatively large and high in the region of the axis of the fastening device, the physician might push against the floor arm with his for her feet during an examination, which can be bothersome. Due to the position and vertical height of the arm, the carrier for the X-ray tube and the detector cannot be lowered completely to the floor given a vertical position of the carrier. In such a vertical position, it would be desirable in a few cases to be able to lower the X-ray tube and the detector by another 4 to 5 cm, so that a good working height is provided for the physician, but this approximately corresponds to the vertical height of the arm. This is a limitation of the adjustment possibilities of the X-ray tube and the detector. Besides, the floor arm and the base restrict the access to the patient.
An object of the present invention is to provide an X-ray examination apparatus with a stand of the aforementioned type, which is relatively simple and compact in its structure and which, in connection with an examination table, the carrier, without disturbing stand parts under the table, can be rotated 90xc2x0 in both directions from a head-adjusted position into vertical lateral positions without changing the position of the isocenter. Another object is to provide such an apparatus which allows the carrier for the stand to be lowered to the floor.
This object is inventively achieved in an X-ray examination apparatus of the type described above wherein the arm arrangement is composed of at least two arms, which are mounted in different planes, with the respective free ends of these arms being rotatably connected to one another around a vertical shaft, and wherein the respective lengths of the arms, depending on the position of the vertical shaft at the base and on the distance of the rotational axis of the support from the central beam for the X-ray tube and the detector, are dimensioned such that the curved carrier, by means of the arms, can be rotated around an intersecting point, which is formed by the central beam cutting the center line of the examination table with respect to the centrally head-adjusted stand. A stand that is simple and compact regarding its structure is achieved due to the fashioning of the arm arrangement and due to the lengths of the arms, whereby the carrier of the stand can be rotated 90xc2x0, with a fixed-position isocenter, from a head-adjusted position into a laterally positioned vertical position at the one side of the examination table, or can be rotated 90xc2x0 into a laterally positioned vertical position at the other side of the examination table. Disturbing parts under the table are avoided by the described structure of the stand. The physician""s team can now choose from which side they wish to most easily access the patient.
In an embodiment, the arms are disposed above one another given a centrally head-adjusted stand position. A relatively compact stand results.
The fastening point for the base is inventively placed such that the curved carrier does not touch the base in any position that can be reached by rotation around the intersecting point. It is thereby achieved that the curved carrier can be lowered to the floor.
The brochure xe2x80x9cARCOSKOPxe2x80x9d of Siemens AG shows a ceiling mount with an arm arrangement, having one end that can be rotated around a vertical shaft that is attached to the base and having an opposite end that carries a support The support is connected to a holding device for a curved carrier, which carries an X-ray tube and a detector. Although the arm arrangement is composed of two arms arranged in different planes, the lengths of the arms are not dimensioned such that the carrier can be partially rotated into a lateral vertical position at the one side of the table and partially into a lateral vertical position at the other side of the table given a centrally head-adjusted stand with a fixed-position isocenter.